The general purpose of the research is to study principles of conditioning and learning of psychophysiological reactions. Within that broad area emphasis is upon learned conscious and cognitive control of autonomically mediated behavior. Basic procedures involve presentation of stimuli in the arrangement of Pavlovian conditioning. In this arrangement lights or tones serve as signals, or conditioned stimuli, and a moderately loud noise serves as an adequate stimulus to evoke small changes in brain waves, skin electricity, and heart rate. Specific concern is for the relationships between evoked cortical potentials and electrodermal responses during procedures of classical conditioning of human subjects. Three current projects explore the role of the interstimulus interval upon the nature of the responses, the importance of movement required to follow the second stimulus of a pair upon the late components of the evoked potentials and the anticipatory behavior in the autonomic response; the role of cognitive expectancy in determining response changes; and the effects of verbal labeling on the learning processes.